Solid State Interlocking

7/31/2019 Solid State Interlocking

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Solid State Interlocking-Preparation of Estimate and Schedule

Ashok KumarManager/S&T

Rites Ltd.

[email protected]


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Consideration of yard for SSI

a) The outdoor arrangement is same in most of the cases for a

station with SSI or without SSI.

b) The signalling functions which control field gears is taken as vital

outputs

c) The signalling functions which are received from field are vital

inputs

d) Also some inputs/outputs connected to block instruments are vital

e) The key-in position of Crank handle is also a vital input


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Consideration of yard for SSI

e) All the control commands coming from panel are taken as Non-

Vital inputs.

f) The indications, counters, buzzers etc are taken as Non-Vital

outputs


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Power Supply Arrangements

Depending on the type of SSI being installed the power supply

arrangement will differ for different make of SSIs.

For example Microlok II uses 24v DC

Other manufacturers may use different voltages like Siemens and

AZD Praha

Accordingly the requirement of power for the SSI working to be

catered in the IPS or separately created


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Assessment of Interface with SSI

1. Vital and Non-vital I/O bit calculation

2. Vital and Non-vital board calculation

3. System configuration and serial communication

4. Power calculation

5. Interconnection of various racks and interlocking equipment

6. Manuscript of complete wiring diagram


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Vital Input and Output PCBs

No of Vital Outputs per output card No of vital inputs per card

Suitable for 12V , 24V or 60V DC application.

Spare vital inputs and outputs


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Non-vital Input/output PCB

Each Non-vital I/O PCB has 32 inputs and 32 outputs in

one PCB.

Suitable for 12V or 24V DC application.

Non-vital inputs are Panel push buttons and keys. Non-vital outputs are Panel indication LEDs, counters and

buzzers.


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Calculation of Vital I/O Bits

Gather following information from Interlocking plan:

1. Type of signals, no of aspects,

2. Points / Cross over and type of control / operation

3. Motor points / Hand operated points

4. Level crossings, siding control and crank handles

5. Track circuits

6. Axle counters

7. Block working and controls from and to the block

instruments


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Calculation of Non-Vital I/O Bits

Collect the following information from Panel Diagram:1. Number of push button controls/knob controls and key

controls. (if knobs are used one bit for normal and one bit for

reverse position to be considered)

2. Number of indications, counters, buzzers, bells etc

3. All output relays controlled by SSI are required to be read back

as per RDSO specification

From this information collected from Signalling Plan and

Panel Diagram Vital I/O and Non-Vital I/O bits can be

calculated respectively.


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Example of I/O Bits:

Out doorGear

Vital Output Vital Input Non-vitalInput

Non-vitalOutput

Relays

3A Signalwith routeindicator

DR

HR

UGR

COHR

DECR

HECR

RECR

UECR

COHECR

GN

or N & Rcondition of

knob

DGKE

HGKE

RGKE

COKE

ECR 4

UECR-1

3A Signal DR

HR

DECR

HECR

RECR

GN


knob

DGKE

HGKE

RGKE

ECR 3

2A Signal HR HECR

RECR

GN


knob

HGKE

RGKE

ECR 2


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Out doorGear

VitalOutput

Vital Input Non-vitalInput

Non-vitalOutput

Relays

Points NWR

RWR

NWKR

RWKR

WN or

N & Rpositions of

point knob

NWKE

RWKE

WFKE

QNN1 1

QNNA1 1

TrackCircuit

TPR TKE

TRKE

QNNA1 - 1


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Out doorGear

Vital Output Vital Input Non-vitalInput

Non-vitalOutput

Relays

CrankHandle

CHYR CHLR CHN CHKE

CHKRE

QNN1 - 1

SidingControl

KLYR KLCR KLN orKL N &

KL R

KLINKEKLOUTKE

KLFKE

QNN1-1

LevelCrossing

LXYR LXCR LXN or

LX N &

LX R

LXINKE

LXOUTKE

LXFKE

QNN1-1

QNNA1-1


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Calculation of BoardsAfter finding out final quantity of Vital and Non-vital I/O bits, quantity of various boards can be

derived :

Vital inputCard

Vital OutputCard

Mixed VitalInput/Output Card

Non-Vital InputCard

Non-Vital OutputCard

Microlok II 16 inputbits/Card

16 Output bits/Card

8 Output bits &

8 Input bits/Card

32 input bits and 32 Output bits/Card

AZD Praha ---------

Siemens 8 Inputbits/Card

4 Outputbits/Card

--------- 4 Input bits/Card 4 Output bits/Card

Calculation of Vital Input, Output cards and Non-Vital input, output cards is not

significant at initial estimate size, unless the tenderer quotes in the form of cards

It will be difficult to evaluate on the basis of cards Only the total number of vital inputs/outputs and non-vital inputs/outputs can be

projected, so that the requirement of cards is decided by the tenderer, as seen

from the above the bits per card vary from manufacturer to manufacturer.


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Configuration of SSI system

When the station provided with SSI is quite big, then more SSI units

are to be provided and synchronised

In that case whether the all the SSI units are to be kept at one

place or to be located at appropriate places to be decided

If requirement is to keep the SSI units at respective locations, their

synchronising with the use of OFC or twisted pairs


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Schedule for SSI system- Salient points

1. The SSI system should meet the latest RDSO specification and all

mandatory requirements of the specification need to be complied by

the supplier.

2. While preparing the schedule clear demarcation of work to be done

by indoor(SSI) contractor and similarly the demarcation of outdoorcontractor. As both indoor and outdoor contractors has to work

clubbing outdoor cables to indoor wiring, this is necessary.

3. Requirement of material for indoor work to be specific and clear.

4. Requirement of relays for indoor work whether to include in SSI

schedule or not to be decided. Where specific type of relays need to

be used in that case procurement of such relays to be decided (in

case of Siemens, Westinghouse etc)


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Schedule for SSI system- ..contd

6. Power supply requirements of the SSI and their arrangement

from IPS or individual supply.

7. Requirement of supplies for reading inputs, driving outputs and

interface with panel for indications, buzzers, counters and button

input reading to be decided.

8. Where more than one units are installed, requirement of

additional equipment and synchronisation of the units through

OFC or twisted pairs. In such cases cable paths need to be

different from reliability point of view.

9. Grounding, Surge protection and Earthing of SSI equipment and

measures to control EMI to SSI equipment.

10. Arrangement for protection from dust.


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11. Provision of data logger

12. Both the Hardware and Software should be to SIL level 4

13. Spare capacity for expansion or alterations in the yard upto 20%

and facility for future alterations

14. Training of staff right from maintainer

15. Sufficient spares for the defect of cards and power supplies as

deemed necessary

16. The Software should be developed to Software engineering

standard such as CENELEC with special application to safety

critical application


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17. Requirement of system architecture

1. Single Hardware with diverse software

1. Warm standby

2. Hot Standby

2. 2 out of 2 system with

1. Warm standby

2. Hot Standby

3. 2 out of 3 architecture

18. Requirement of flexibility in application software19. Any other requirements as per practice of individual railways


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Thanks

The End

Solid State Interlocking

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